Melatonin And Gut Health


Welcome to my blog “Melatonin And Gut Health”.

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Since the gut contains at least 400 times more melatonin than the pineal gland, a review of the functional importance of melatonin in the gut seems useful, especially in the context of recent clinical trials. Melatonin exerts its physiological effects through specific membrane receptors, named melatonin-1 receptor (MT1), MT2 and MT3. These receptors can be found in the gut and their involvement in the regulation of GI motility, inflammation and pain has been reported in numerous basic and clinical studies.

How Does Melatonin Help IBS?

The gastrointestinal tract represents the most important extrapineal source of melatonin.


Putative role of melatonin in IBS treatment include (1,  3):

  • Analgesic effects – it may help to alleviate abdominal pain and influence the sensation of abdominal distention in IBS patients.
  • Regulator of gastrointestinal motility – it may improve the bowel habits and alleviate abdominal pain or distention in IBS patients.
  • Sensation to sleep promoter – may be useful to treat the sleep disturbance of IBS patients.
  • Melatonin has mood regulation and anti-stress effects which could help alleviate the abnormal psychological parameters observed in IBS patients.
  • The release of peptides involved in energy balance such as peptide YY

Several well-designed placebo- controlled trials in IBS patients had consistently showed improvement of abdominal pain when taking 3 mg of melatonin with no serious side effect (1).

Melatonin And Motility

Low doses melatonin improves gastrointestinal transit and affect MMC. Melatonin reinforce MMCs cyclic pattern but inhibits spiking bowel activity (2).

Melatonin reduced the tone but not amplitude or frequency of contraction. Melatonin is a promising therapeutic agent for IBS with activities independent of its effects on sleep, anxiety or depression. Since of its unique properties melatonin could be considered for prevention or treatment of colorectal cancer, ulcerative colitis, gastric ulcers and irritable bowel syndrome (2).

Melatonin may also have a beneficial effect in reversing lipopolysaccaride-induced motility disturbances. LPS are remnants of gram-negative bacteria, normal inhabitants of the large intestine. But if these overgrow, we can end up with a high LPS burden in the gut that may influence motility.


Melatonin is a relatively safe drug that possesses potential in treating IBS. Its attractiveness also stem from its relative low cost to the patients. Future studies should focus on melatonin effect on gut mobility especially in IBS-C patients as well as its true central nervous system effect in view of high placebo rate often observed in IBS patients (1).

The uncommonly high-safety profile of Mel. also bolsters this conclusion.


  1. Melatonin for the treatment of irritable bowel syndrome (click here)
  2. Melatonin and serotonin effects on gastrointestinal motility (click here)
  3. Distribution, function and physiological role of melatonin in the lower gut (click here)
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